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Date:   Sat, 25 Jan 2020 10:53:21 +0100 (CET)
Message-Id: <20200125.105321.1408762540319080985.davem@davemloft.net>
To:     mpe@ellerman.id.au
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        security@kernel.org, ivansprundel@ioactive.com, vishal@chelsio.com
Subject: Re: [PATCH] net: cxgb3_main: Add CAP_NET_ADMIN check to
 CHELSIO_GET_MEM
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20200124094144.15831-1-mpe@ellerman.id.au>
References: <20200124094144.15831-1-mpe@ellerman.id.au>
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From: Michael Ellerman <mpe@ellerman.id.au>
Date: Fri, 24 Jan 2020 20:41:44 +1100

> The cxgb3 driver for "Chelsio T3-based gigabit and 10Gb Ethernet
> adapters" implements a custom ioctl as SIOCCHIOCTL/SIOCDEVPRIVATE in
> cxgb_extension_ioctl().
> 
> One of the subcommands of the ioctl is CHELSIO_GET_MEM, which appears
> to read memory directly out of the adapter and return it to userspace.
> It's not entirely clear what the contents of the adapter memory
> contains, but the assumption is that it shouldn't be accessible to all
> users.
> 
> So add a CAP_NET_ADMIN check to the CHELSIO_GET_MEM case. Put it after
> the is_offload() check, which matches two of the other subcommands in
> the same function which also check for is_offload() and CAP_NET_ADMIN.
> 
> Found by Ilja by code inspection, not tested as I don't have the
> required hardware.
> 
> Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied and queued up for -stable.